Iaho. Though this name is more fully treated under the word“Yaho” and “Iao”, a few words of explanation will not be found amiss. Diodorus mentions that the God of Moses was Iao; but as the latter name denotes a “mystery god”, it cannot therefore be confused with Iaho or Yaho (q.v.). The Samaritans pronounced it Iabe, Yahva, and the Jews Yaho, and then Jehovah, by change of Masoretic vowels, an elastic scheme by which any change may be indulged in. But “Jehovah” is a later invention and invocation, as originally the name was Jah, or Iacchos (Bacchus). Aristotle shows the ancient Arabs representing Iach (Iacchos) by a horse, i.e., the horse of the Sun (Dionysus), which followed the chariot on which Ahura Mazda, the god of the Heavens, daily rode.
Source: H.P.Blavatsky - The Theosophical Glossary